freak at codepimps.org
Wed Oct 15 09:58:43 CEST 2003
On October 15, 2003 07:29 am, Michael Thaler wrote:
> Yesterday I tried to make a small project using KDevelop3. I intend to
> write a very simple program that uses the krita rendering classes. I
> just want something that allows me to load/save an image and to draw
> single points etc.
> The main purpose of this is to have something simple to play with,
> e.g. find out how the rendering stuff really works, find out how quick
> the screen is updated for different tile sizes etc.
> It was easy to import KisTile, KisTileMediator, KisTileMgr,
> KisPixelData and other basic classes. It is not easy at all to import
> KisPainter and KisPaintDevice because these classes depend on
> KisLayer, KisImage and KisDoc. KisImage depends on KisLayer,
> KisPaintDevice, KisPainter and many other things. KisDoc depends on
> KisImage, KisLayer, etc. while KisLayer depends on KisImage and
The layer or image only needs an image to indicate it's owner, nothing else.
You have a constructor that takes no KisImage argument, i.e. no owner, hence
it is optional.
I don't see any reference from KisPainter to KisLayer or KisDoc from
KisPainter. The reference to the owning image have to do with the undo
commands, not the painter proper.
I don't see any reference from KisPaintDevice to KisDoc, except again for undo
commands, this is also optional. No references to KisLayer. The KisImage,
again, is for undo.
> This makes it really hard to reuse any part of Krita and it also makes
> the code very hard to understand. Why are there all these circular
> dependencies? IHMO this is not a good design at all.
Really? I guess I should read scrap that composite design pattern after all
and just copy & paste that code then :)
However, you do have a point about KisPaintDevice using a KisDoc, KisDoc
should inherit privately from an interface to handle this.
The owning image aggregate could be made a KisPaintDevice instead of a
KisImage, although it helps encapsulation, it hurts correctness here since we
don't want an owning image to be anything else than an image.
> I think there really should be a hirachy:
> - KisPaintDevice is what KisPainter uses for rendering.
Nope, KisPainter is what you use to paint on a KisPaintDevice.
> - KisLayer inherrits KisPainter and offers some additional methods.
?!? KisLayer inherits from KisPaintDevice right now.
> - KisImage contains several layers and has methods to manage these
That is what is has, but KisImage is also a KisPaintDevice.
> - KisDoc contains one (or more KisImages)
That is what is has.
> KisPainter and KisPaint device should know nothing about KisDoc and
> KisImage etc.
The rational for KisImage is given above, but you have a point about KisDoc
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